Regenerative piston excavator



Jan. 13, 1970 D. E. NELSON REGENERATIVE PISTON EXCAVATOR Filed March 22, 1968 F IG 3 ZNVENTOR United States Patent 3,489,230 REGENERATIVE PISTON EXCAVATOR Daniel E. Nelson, Pacific Grove, Calif., assignor to General Kinetics Corporation, Monterey, Calif., a corporation of California Filed Mar. 22, 1968, Ser. No. 715,222 Int. Cl. E21b 1/06, 3/08, /00

U.S. Cl. 175-93 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an excavator having regenerative air cycle piston combustion with staged compression, impact reciprocation, blasting combustion and rotary bit.

Objects of this invention are to provide impact reciprocation, blasting combustion and rotative cutting separately or in combinations thereof at the face of a mine or well.

Advantages of this invention are that it does not require the time and cost of lowering and raising drill stems in wells as in present practice. This saves over 75 percent of the time and cost of well drilling in present practice.

Further advantages are that this invention makes automatic underground mining feasible. One or a multiplicity of bits can be operated at a mine face and the ore removed by conveyors. The size of the bits can be varied for large or small vein thickness. Over 75 percent of the worlds mineral reserves comprising the worlds richest ore is in veins too thin for economical recovery with present mining methods. This invention more than triples the recoverable amount of world mineral supplies by making the rich thinner veins accessible.

Deeper oil wells can be drilled economically. Recoverability of the worlds known oil reserves can be increased over four times by using this invention in its various forms.

The use or non use of combustion for blasting at the well or mine face can be employed where needed or not employed where ore combustability or softness make blasting dangerous or unnecessary.

Previous practices using a piston with air cycle co1nbustion for excavating devices have not had the advantages of staged compression and the option of a reciprocating impact bit, a rotational bit and a high build up of combustion pressure for blasting or pressurization as provided by this invention. Air regenerative ignition and cooling also have not been used or known in the manner introduced by this invention. A piston with combustion pressure for blasting effect in excavating has been used in previous practice in a different manner requiring a crankshaft and without staged compression, regeneration, or a bit. A free piston has been used in previous practice in a manner different from this invention and without combustion blasting means, regeneration and spring resiliency.

This invention is illustrated in the accompanying drawings as follows:

FIG. 1 is a cutaway side view illustrating a double acting piston form of this invention and having a combination of impact reciprocation, combustion blasting and rotary bit.

FIG. 2 is a cutaway side view illustrating a double acting piston form of this invention and having a combination of impact reciprocation and rotary bit.

FIG. 3 is a cutaway side view illustrating a single acting piston form of this invention and having a combination of impact reciprocation and blasting combustion.

FIG. 4 is a top section view of one-way valves used primarily in combustion areas in this invention.

ICC

The operation of these improvements in excavators is accomplished in the following manner. Referring to FIG. 1, a power shaft 1 is extended in slidable contact through a head of compressor cylinder 2, through heads of power cylinder 3 and into combustion chamber 4. A compressor piston 5 and a power piston 6 are attached to the power shaft in the compressor and power cylinders respectively. A transverse guide 7 is extended between a base plate 8 and a combustion chamber base 9. A rotatable bit 10 with a drive sleeve 11 is rotatably attached to the base plate. A counterbevelled cam drive gear 12 is attached to the bit. Drive teeth 13 are extended from the power shaft in slidable contact with the transverse guide and counterbevelled cam drive gear. Combustion chamber ports 14 are extended through the combustion chamber wall in line with rotatable blasting bit ports 15.

Air flow through the FIG. 1 form of the invention is introduced through intake air line 16 attached to housing 17. Intake air ports with one-way valves 18 and 19 are provided at compressor cylinder heads 20 and 21 respectively. The compressor piston is hollow and is provided with intake air ports with oneway valves 22 and 23 in compressor piston heads 24 and 25 respectively. The power shaft is hollow and is provided with power shaft intake ports 26. Air outlet ports 27 are provided in the power shaft in heat exchange chamber 28 between cylinder walls 29 and heat exchanger walls 30. Valved inlet ports 31 and exhaust ports 32 are provided in the power cylinder and exhaust line 33 is employed to conduct power cylinder exhaust gasses from the power cylinder and from the excavator. Blasting combustion chamber intake ports 34 are positioned in the power shaft between the base plate and the power cylinder. A combustion chamber intake port with one-way valve 35 is provided where the hollow power shaft is extended in slidable contact into the combustion chamber.

Fuel injection in the FIG. 1 form of this invention is provided by cylinder and blasting combination chamber injection pumps 36 and 37 respectively. The injector pumps can be operated by injector drive cams 38 on the drive sleeve or by contact of injector pump actuators 39 with the drive teeth. Actuation of the blasting combustion chamber injector pump by the drive members and actuation of the cylinder injector pump by the drive sleeve cam is illustrated in FIG. 1. Further illustration of the cylinder injector pump actuation by rotary drive cams is provided in FIG. 2. Fuel injection lines 40 are provided to convey fuel from the cylinder injector pumps to fuel injector nozzles 41 and 42 in the power cylinder heads. A combustion chamber injector nozzle 43 is attached to the combustion chamber injector pump.

Combustion in the power cylinder is caused at the end of each stroke of the power piston in a double-acting mode in the FIG. 1 form. The power shaft is caused to travel in reciprocating motion and thereby to cause the compressor piston and drive teeth to travel in the same reciprocating motion. Air is drawn through the compressor intake air ports at each compressor cylinder head and compressed through the compressor outlet ports at each compressor piston head in double-acting piston mode in conjunction with the one-way valves that prevent return flow of compressed air. The compressed air is directed into the power shaft through the power shaft intake ports and out of the power shaft through the power shaft outlet ports. The air is then heated in the process of cooling the power cylinder by appropriate heat exchange members added to the outside of the power cylinder.

The air is then directed to two different locations. Part of the heated intake air is directed into the power cylinder after exhaust is released at the exhaust end of each stroke of the power piston. The compressed and heated air in the power cylinder is then further compressed and heated by the return compression stroke such that fuel injected at the end of the compression stroke can be ignited.

The other location to which the compressed and heated air is directed is into the blasting combustion chamber. It is channelled through the power shaft combustion chamber inlet port and through the valved combustion chamber inlet port.

Air in the combustion chamber is prevented from escaping from the blasting combustion chamber by rotation of the rotatable blasting bit to where blasting bit ports are not in line with combustion chamber outlet ports. The combustion chamber outlet ports can be closed during two strokes of the piston in order to obtain a large charge of compressed and heated air into which fuel can be iniected and blasting combustion gas pressure generated. Blasting combustion gasses are released at the same time that impact occurs from the reciprocating piston.

Combustion gasses can be retained in the chamber until the pressure thereof has accumulated to a desired level and then released in accordance with the timing of the outlet ports. This causes extremely high pressures similar to weapons practices but not achieved in blasting previously.

Combustion in the power cylinder or in the blasting combustion chamber or in both can be accomplished partially or totally by regenerative heat from the engine after original ignition. Heat of the engine is added to the intake air after partial compression when the air is conlined and the concentration of oxygen in the air can not be diminished to require greater volumes of air. Only minor pressure to be overcome in further compression is added by heating the air. The compressed intake air heat can be 1,000 F. to 1,500 F. prior to ignition at either the power cylinder or the blasting combustion chamber. This is several times the ignition heat required for petroleum or other anticipated fuels.

Heat of the compressed intake air can be varied according to the ratio of fuel to air and to the amount of either that is added. A near stoichiometric ratio of fuel to air would cause suflicient heat for ignition without spark or compression ignition at either or both locations. A :ooler combustion with cooler inlet temperatures requiring spark or ignition may be desirable, depending on the use. Large enough exhaust ports to allow an airflow overrun at either or both locations can be achieved for a cooler combustion with a spark ignition system. Cooler combustion with compression ignition can be achieved by a low fuel injection rate in conjunction with a high compression ratio at either or both locations. Valving separate from the sleeve valves illustrated is desirable when the compression ratios at the two locations are different.

The form of the invention illustrated in FIG. 2 has impact reciprocation in conjunction with a rotary bit and regeneration achieved in the manner described above. However, it does not have a blasting combustion chamber. All air compressed is used in the power cylinder. The compressor piston can be smaller and the bit larger relative to the size of the power piston as illustrated in this form of the invention.

The bits can be fitted with various types of teeth, blades, cutting or excavation members. Smaller and harder bits can be used for harder ore while larger bits and blades or a screw can be used for softer ores. For excavating slurry occurring naturally or created by adding a liquid or for recovering a liquid, a screw or bladed bit with a pumping action is advantageous. This is particularly applicable to the FIG. 2 form of this invention. A counter vibration damper may even be advisable with the FIG. 2 for some excavating conditions where impact reciprocation is, not desirable or necessary. A screened bit can be used to achieve non-rotary impact with blasting combustion and without blasting combustion w th FIGS, 1 and 2 respectiv y Pressurization of an ore body with exhaust gasses for excavation can be achieved separately from rotation by use of the FIG. 1 form with a screened bit. Reciprocation also could be omitted by adding a vibration damper. Injecting water into the blasting combustion chamber in addition to fuel for additional pressure and mass from steam can be accomplished by employing the high heat of combustion caused by a stoichiometric fuel-air ratio as explained above.

The form of this invention illustrated in FIG. 3 has impact reciprocation and blasting combustion. Referring to FIG. 3, staged compression is achieved with a single acting power piston 44 that is actuated towards a single cylinder head 45 by a resiliency spring 46. Air is drawn into a single acting compression piston 49. The power piston and compressor piston can be on opposite sides of a common piston as shown in FIG. 3. Pressure from the resiliency spring is transferred by a single acting piston power shaft 50.

Travel of the piston towards the cylinder head pumps air from heat exchange chamber 51 that is formed between compressor cylinder walls 52 and reciprocating power cylinder walls 53. The air is directed through power cylinder inlet ports 54 having one-way valves and into power cylinder 55. Air in the cylinder is then compressed into pivotal air cell 56 through two way power cylinder head port 57 and air cell intake port 58.

Return travel of the piston causes air in the compression cylinder to be compressed into the heat exchange chamber through heat exchange inlet port 59 with oneway valve. Air is retained in the heat exchange chamber during the return travel by a higher combustion pressure against the inlet valve in the power cylinder until near the end of the return stroke.

The pivotal air cell is actuated in alternate circular directions by air cell control member 60 attached to the reciprocating power cylinder walls and in slidable contact with air cell actuating members 61. The air cell is pivoted in one direction when the piston and power cylinder walls travel away from the cylinder head. Opposite pivotal direction travel of the air cell is caused when the piston travels towards the cylinder head.

Combustion is caused in the air cell when inlet port 58 is open and exhaust blasting port 62 is closed. A portion of the combustion pressure is directed through the inlet port and all air cell ports to be closed momentarily. A high pressure build up occurs in the air cell for highly effective blasting practice. Air cell exhaust port 63 is then opened by the further return travel of the piston and sleeve and the high gas pressures for blasting are released through blasting combustion pressure ports 64. Further travel of the piston to near the end of its return stroke causes the air cell to rotate to where air cell port 58 is in communication with scavenge port 65. Combustion pressure in the power cylinder is released through the scavenge port. Compressed air in the heat exchange chamber is then released through the combustion chamber inlet port; into the power cylinder; through the scavenge port; and out the air cell exhaust port. The scavenge port is timed by proper size to remain open until a sufficient amount of air for scavenging and limited cooling through air flow overrun has been permitted to flow. The port is then closed as the piston travels towards the cylinder head and the remaining air in the heat exchange chamber and in the power cylinder are compressed into the air cell.

Fuel for injection at the end of a stroke is supplied through fuel line 66 having one-way inlet valve 67. A plunger 68 around the power shaft is forced away from compressor base 69 by fuel pump spring 70 when a pump shoulder 71 on the power shaft travels in a return stroke with the piston. The plunger is washer shaped and the resiliency spring is a circular reversed chevron form in the illustration. Fuel is drawn into fuel pump cylinder 72 during the return stroke at the piston. The

pump shoulder causes the plunger to move forward to pump fuel through fuel injector line 73 and to inject fuel through injector 74 as the piston approaches the cylinder headHA venturi action is caused as the fuel enters the air cell with the compressed air and atomization of fuel is further aided.

Spark can be achieved in conjunction with fuel injection if desired. A means of achieving spark is provided by a coil 75 on the power shaft in reciprocative power generating relationship with magnets 76. A capacitor 77, here washer shaped, is caused to accumulate power obtained from the coil and to release the power through electrical conduction line 78 when the piston is near the cylinder head. The coil, in the illustration 9. pump ridge also, is moved against ignition spring 79. The capacitor is moved against the compressor base or pump plunger in the illustration and is forced towards the coil to conduction contact point 80 where the power in the capacitor can be released to spark plug 81.

A bit 82 for the FIG. 3 form can be screened for pressurized excavation without cutting effect or it can be provided with various points or blades for impact and blasting excavation.

The one-way valve illustrated in FIG. 4 is particularly recommended for combustion heat areas and is excellent for all uses in this invention. It is shown in use for the blasting combustion chamber inlet port in FIG. 1, at the power cylinder inlet ports in FIG. 3 and at the compression cylinder air inlet ports in FIG. 3. Its advantages are that springs are not required in the high heat areas of use and it can be sturdily built for high pressure. It is comprised of a wafer 83 in a short cylinder 84 with a step 85 to a smaller diameter of the cylinder. The wafer is seated against the step by return pressures of the pressurized material and sealing of the return material is achieved. Inflow of pumped material moves the wafer away from the seat to a wafer retainer 86 and allows the material to flow between the wafer and the seat. Channels 87 in either the wafer or in the cylinder are provided to permit the material to flow pastthe wafer.

Heat exchange members 88 can be added for heat exchange eifectiveness in the regenerative cycle.

A more efficient device for excavating ore of all types and forms from the earth automatically and economically has been invented and all changes and modifications that may be made without departing from the spirit of the invention are contemplated within the scope of the appended claims.

I claim:

1. An excavator having:

an air compressor cylinder with compressor piston and valved inlet and outlet ports,

a power cylinder with power piston and valved inlet and outlet ports,

a power shaft attached to the power piston and compressor piston,

a compressed air chamber in air transfer communication between the compressor piston and the power piston,

a housing in contact with the power cylinder,

an excavation bit attached to the housing in power transfer relationship with the power piston,

an air supply means in communication with inlet ports of the compressor cylinder, and

a fuel supply means in communication with the power cylinder.

2. In an excavator substantially as described in claim 1, double acting pistons and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet ports in communication with the air supply means and separate valved ports in communication with the compressed air chamber,

a double acting power piston on the power shaft, and

a double headed power cylinder having valved inlet and outlet ports.

3. In an excavator substantially as described in claim 1, double acting pistons with a hollow shaft and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet and outlet ports,

a hollow power shaft having inlet ports in communication with compressor cylinder outlet ports in the compressor piston and having outlet ports in communication with the compressed air chamber.

4. In an excavator substantially as described in claim 1, double acting pistons in air regenerative heat exchange cycle and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet ports in communication with an air supply means and separate valved ports in communication with the compressed air chamber,

a double acting power piston on the power shaft,

a double headed power cylinder having valved inlet and outlet ports,

heat exchange members extended in air regenerative heat exchange communication from the power cylinder into the compressed air chamber.

5. In an excavator substantially as described in claim 1, a reciprocative impact bit with double acting piston and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet ports in communication with the air supply means and separate valved ports in communication with the compressed air chamber,

a double acting power piston on the power shaft,

a double headed power cylinder having valved inlet and outlet ports, and

an impact bit attached to the housing.

6. In an excavator substantially as described in claim 1, an impact rotary bit with double acting pistons and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet ports in communication with the air supply means and separate valved ports in communication with the compressed air chamber,

a double acting power piston on the power shaft,

a double headed power cylinder having valved inlet and outlet ports,

a bit rotatably attached ot the housing,

a transverse guide attached to the housing,

a counterbevelled cam drive gear attached to the bit, and cam drive members extended radially from the power shaft in slidable contact with the transverse guide and with the counterbevelled cam drive.

7. In an excavator substantially as described in claim 1, an impact blasting and rotary bit with double acting pistons and having:

a double acting compressor piston positioned separately from the power piston on the power shaft,

a double headed compressor cylinder having valved inlet ports in communication with the air supply means and separate valved ports in communication with the compressed air chamber,

a double acting power piston on the power shaft,

a double headed power cylinder having valved inlet and outlet ports,

a bit rotatably attached to the housing,

a transverse guide attached to the housing,

a counterbevelled cam drive gear attached to the bit,

cam drive members extended radially from the power shaft in slidable contact with the transverse guide and with the counterbevelled cam drive gear,

a blasting combustion chamber attached to the housing inside the bit, A

a valved conduit in communication from the coma power cylinder sleeve attached to the power piston and extended in slidable contact with the outside periphery of the power cylinder head,

a resiliency means with compressible resiliency force against the power shaft in the direction of the power pressed air channel to the blasting combustion cylinder head, chamber, and a blasting combustion chamber,

valved outlet ports in communication from the blasting valved ports in communication with the power cylinder combustion chamber to the outside of the bit. and the blasting combustion chamber, and

8. In an excavator substantially as described in claim 1, 10 valved outlet ports in communication with the blasting an impact blasting and rotary bit with double acting combustion chamber and the outside of the bit. pistons and air regenerative cycle having: 10. In an excavator substantially as described in claim a double acting compressor piston positioned separately 1, single acting pistons with rotatable air cell and resiliency from the power piston on the power shaft, spring and having:

a double headed compressor cylinder having valved inlet a power cylinder sleeve attached to the power piston ports in communication with the air supply means and extended in slidable contact with the outside and separate valved ports in communication with the periphery of the power cylinder head, compressed air chamber, a resiliency spring compressible against the power shaft a double acting power piston on the power shaft, in the direction of the power cylinder head,

a double headed power cylinder having valved inlet and a pivotal air cell blasting combustion chamber at the outlet ports, power cylinder head,

a bit rotatably attached to the housing, a two Way port in the power cylinder head,

a transverse guide attached to the housing, a scavenge port in the power cylinder head,

a counterbevelled cam drive gear attached to the bit, an exhaust blasting port in the housing at substantially cam drive members extended radially from the power the opposite side of the air cell from the power cylinshaft in slidable contact with the transverse guide and der head, with the counterbevelled cam drive gear, blasting combustion pressure ports in communication a blasting combustion chamber attached to the housing with the exhaust blasting port and the outside periphinside the bit, cry of the bit,

a hollow power shaft having inlet ports in communiair cell actuation members on the air cell,

cation with compressor cylinder outlet ports in the an air cell actuation means attached to the power cylincompressor piston and having outlet ports in comder sleeve and in movable contact with the air cell munication with the compressed air chamber, actuation members,

heat exchange members extended in air regenerative an air cell intake port positioned in the air cell such heat exchange communication from the power cylinthat it becomes in communication with the power der into the compressed air chamber, cylinder head port when the power piston approaches a hollow power shaft extended in slidable contact from the power cylinder head and becomes in communithe power piston into the blasting combustion cation with the power cylinder head scavenge port chamber, when the power piston approaches the end of a power blasting combustion chamber inlet ports in cornmunistroke, and

cation between the compressed air chamber and the an air cell exhaust port positioned in the air cell such hollow power shaft extended into the blasting that it becomes in communication with the exhaust chamber, blasting port in the housing during a late portion of a valved blasting combustion chamber inlet port in combustion strokes and an early portion of return communication between the hollow shaft and the strokes of the power piston. blasting combustion chamber,

outlet ports in the bit in alternate communication and References Cited noncommunication with the blasting combustion UNITED STATES PATENTS chamber outlet ports as the bit is rotated, and

1,082,901 12/1913 Perkins 175100 X i l ff g fiiig fg Power cylmder and blastmg 1,087,632 2/1914 Benjamin 175100X 3,205,953 9/1965 Ferrabee 175-15 X 9. In an excavator substantially as described 1n claim 1, 3,212,592 10/1965 Rolseth 175 15 X single acting pistons, resiliency means and blasting combustion chamber and having: NILE C. BYERS, JR., Primary Examiner 

